Spring retainer for power-operated tool



Oct. 3, 1967 f 3,345,079

SPRING RETAINER FOR POWER-OPERATED TOOL- J. L. WICKHAM Filed 001:. 21,1965 Q INVENTOR JOHN L. WICKHAM ATTORNEY United States Patent .0

3,345,079 SPRING RETAINER FOR POWER-OPERATED 'roor.

John L. Wickham, Baltimore, Md., assignor to The Black ABSTRACT OF THEDISCLOSURE A power-operated tool is provided with an improved springretainer. The retainer is generally in the form of a coil spring. Oneend of the coil spring is mounted on the barrel of the tool. The otherend has at least one loop formed with a portion extending radiallyinwardly. This inwardly extending portion engages an annular shoulder ona suitable tool element, such as a chisel, which is received in thebarrel of the tool. Thus the chisel is retained against ejection out oftool during its operation. One end of the loop is received backunderneath itself, thereby improving the resiliency of the coil springand the retention of the chisel.

Brief summary of the invention The object of the present invention is toprovide a spring retainer which has three advantages: (1) an improvedresiliency; (2) an improved retention; and (3) a facility for quickremoval.

In accordance with the invention, the improved spring retainer isprovided with substantially a complete coil or convolution between theend of the barrel and the loop portion of the retainer which engages thechisel, with the end of the loop being received back underneath itself,thereby improving its resiliency and its retaining function.

These and other objects of the present invention will become apparentfrom a reading of the following specification, taken in conjunction withthe enclosed drawings, in which:

Description of the drawings FIGURE 1 is a perspective of the improvedspring retainer;

FIGURE 2 shows the manner in which the spring retainer is threadablymounted on the barrel of a poweroperated tool for retaining amufller-cutting chisel, the tool and the chisel being shown in brokenlines;

FIGURE 3 is an enlarged top plan view of the spring retainer, lookingdown on the loop portion thereof, showing the manner in which the loopis tucked back (or received back) underneath itself;

FIGURE 4 is an end elevation;

FIGURE 5 is a side elevation; and 7 FIGURE 6 shows, first, the manner inwhich the retainer preferably engages threads formed on the barrel ofthe tool; secondly, the manner in which a portion of the loop engages acollar on the chisel to retain the chisel in the tool; and thirdly, thepreferred use of two complete convolutions between the loop and the endof the barrel.

Detailed description 3,345,079 Patented Oct. 3, 1967 to threadablyengage threads 12, see FIGURE 6, formed manner, the spring retainer isseated on the too]. To facilitate its threaded engagement, a hook 15 isformed on its end thereof for engagement by the operator.

The convolutions 11 terminate forwardly of the barrel in a loop 16, seeFIGURE 3. This loop 16 has an inward portion 17 (directedradially-inwardly of the convolutions) which engages a collar 18 on thechisel 19 so as to retain the latter against ejection out of the barrelduring the operation of the tool. This inward portion 17 of the loop ismovable radially away from the chisel so as to facilitate a manualremoval of the chisel from the barrel of the tool.

In the improved spring retainer 10 of the present invention, and unlikethe prior art and prior commercial practices, the end 20 of the loop isreceived back underneath itself as shown more clearly in FIGURES 1 and3. The end 20 of the loop may be tucked underneath itself, as shown inFIGURE 3, or it may first pass over itself and then be tuckedunderneath, if desired. Also, substantially one, and preferably twocomplete convolutions, see

FIGURE 6, are provided between the end of the loop and the end of thebarrel.

With this arrangement, the objects of the invention are fulfilled. Thespring retainer has improved resiliency and improved retention of thechisel, yet facilitates a quick removal of the chisel from the tool.

In one prior commercial practice, the end of the loop is brought all theway back to one of the first convolutions on the barrel, and whileproviding adequate retention, nevertheless substantially detracts fromthe resiliency of the retainer. Good resiliency of the retainer isdesirable during the operation of the tool; otherwise the retainers tendto fall prematurely. In most prior commercial practices, theconvolutions terminate forwardly of the barrel directly in the end loopwhich engages the collar on the chisel. This does not have goodretaining power and hence is undesirable.

Obviously, many modifications may be made without departing from thebasic spirit of the present invention; and accordingly, within the scopeof the appended claims, the invention may be practiced other than hasbeen specifically described herein.

I claim:

1. The combination with a power-operater tool, of a spring retainer fora tool element mounted in a barrel portion of the tool, said springretainer having means engaging the barrel of the tool for seating saidspring retainer on the tool, said spring retainer having convolutionsterminating forwardly of the barrel in a loop, the loop having a portionthereof formed radially inwardly of the convolutions for normallyengaging a cooperating portion of the tool element, thereby to retainthe tool element against ejection out of the barrel during operation ofthe tool the portion of the loop engaging the tool element being movableradially away from the tool element to facilitate manual removal of thetool element from the barrel of the tool, and the end of the loop beingreceived back underneath itself, thereby improving the resiliency ofsaid spring retainer and the retention of the tool element.

2. The combination with a power-operated tool, of a spring retainer fora tool element mounted in a barrel portion of the tool, saidspringretainer comprising a series of convolutions threadably engaging thebarrel of the tool, thereby seating said spring retainer on the tool,the convolutions terminating forwardly of the barrel in a loop, the loophaving a portion thereof formed radially inwardly of the convolutionsfor normally engaging a cooperating portion of the tool element, therebyto retain the tool element against ejection out of the barrel duringoperation of the tool, the portion of the loop engaging the tool elementbeing movable radially away from the tool element to facilitate manualremoval of the tool element from the barrel of the tool, the end of theloop being received back underneath itself, and substantially onecomplete convolution between the end of the barrel and 4 the end of theloop which is received back underneath itself.

References Cited UNITED STATES PATENTS 1,176,343 3/1916 Christiansen279-19.1 1,796,487 3/1931 Stevens 2.7919 2,051,670 8/1936 Anton 26712,445,551 7/1948 Barry 27919.6

FOREIGN PATENTS 324,558 8/ 1920 Germany.

ROBERT C. RIORDON, Primary Examiner.

1. THE COMBINATION WITH A POWER-OPERATER TOOL, OF A SPRING RETAINER FORA TOOL ELEMENT MOUNTED IN A BARREL PORTION OF THE TOOL, SAID SPRINGRETAINER HAVING MEANS ENGAGING THE BARREL OF THE TOOL FOR SEATING SAIDSPRING RETAINER ON THE TOOL, SAID SPRING RETAINER HAVING CONVOLUTIONSTERMINATING FORWARDLY OF THE BARREL IN A LOOP, THE LOOP HAVING A PORTIONTHEREOF FORMED RADIALLY INWARDLY OF THE CONVOLUTIONS FOR NORMALLYENGAGING A COOPERATING PORTION OF THE TOOL ELEMENT, THEREBY TO RETAINTHE TOOL ELEMENT AGAINST EJECTION OUT OF THE BARREL DURING OPERATION OFTHE TOOL THE PORTION OF THE LOOP ENGAGING THE TOOL ELEMENT BEING MOVABLERADIALLY AWAY FROM THE TOOL ELEMENT TO FACILITATE MANUAL REMOVAL OF THETOOL ELEMENT FROM THE BARREL OF THE TOOL, AND THE END OF THE LOOP BEINGRECEIVED BACK UNDERNEATH ITSELF, THEREBY IMPROVING THE RESILIENCY OFSAID SPRING RETAINER AND THE RETENTION OF THE TOOL ELEMENT.